Cannot toot from new iOS app "Mast"

Try to toot, get an error. Toot saved in drafts. Pleroma log shows this:

Nov  1 22:22:15 colo pleroma: Request: POST /api/v1/statuses
Nov  1 22:22:15 colo pleroma: ** (exit) an exception was raised:
Nov  1 22:22:15 colo pleroma:     ** (Cachex.ExecutionError) deps/ecto/lib/ecto/repo/queryable.ex:348: value `""` in `where` cannot be cast to type :id in query:
Nov  1 22:22:15 colo pleroma:
Nov  1 22:22:15 colo pleroma: from a in Pleroma.Activity,
Nov  1 22:22:15 colo pleroma:   where: a.id == ^"",
Nov  1 22:22:15 colo pleroma:   select: a
Nov  1 22:22:15 colo pleroma:
Nov  1 22:22:15 colo pleroma:         (cachex) lib/cachex.ex:1447: Cachex.unwrap_unsafe/1
Nov  1 22:22:15 colo pleroma:         (pleroma) lib/pleroma/web/mastodon_api/mastodon_api_controller.ex:355: Pleroma.Web.MastodonAPI.MastodonAPIController.post_status/2
Nov  1 22:22:15 colo pleroma:         (pleroma) lib/pleroma/web/mastodon_api/mastodon_api_controller.ex:1: Pleroma.Web.MastodonAPI.MastodonAPIController.action/2
Nov  1 22:22:15 colo pleroma:         (pleroma) lib/pleroma/web/mastodon_api/mastodon_api_controller.ex:1: Pleroma.Web.MastodonAPI.MastodonAPIController.phoenix_controller_pipeline/2
Nov  1 22:22:15 colo pleroma:         (pleroma) lib/pleroma/web/endpoint.ex:1: Pleroma.Web.Endpoint.instrument/4
Nov  1 22:22:15 colo pleroma:         (phoenix) lib/phoenix/router.ex:278: Phoenix.Router.__call__/1
Nov  1 22:22:15 colo pleroma:         (pleroma) lib/pleroma/web/endpoint.ex:1: Pleroma.Web.Endpoint.plug_builder_call/2
Nov  1 22:22:15 colo pleroma:         (pleroma) lib/plug/debugger.ex:122: Pleroma.Web.Endpoint."call (overridable 3)"/2